VEGETATION OF MOUNT DIABLO. 167 
the Coast Range proper, and by the broad stretches of the 
Santa Clara Valley. Mt. Diablo, on the other hand, is 
scarcely more than thirty miles from the ocean, about twenty 
miles from San Francisco Bay, and has neither any stretches 
of plain, nor any ridge of very lofty hills intervening as 
barriers against the influences of the ocean. Indeed Mt. 
Diablo and its outlying northern and western spurs are 
formed almost into a peninsula by those connected and half 
encircling bodies of water, the bays of San Francisco, San 
Pablo and Suisun. 
Neither the higher slopes nor the summit of this moun- 
tain have ever been tenanted except for a few weeks at a 
time, and that at the dry season of the year; consequently 
there are no statistics meteorological from which to speak 
of the humidity of the summit during the rainy season; but 
the summer fogs that prevail in the Coast Range generally 
envelop the top of Diablo as they do no other summit 
belonging to the inner Range. Its vegetation is therefore 
naturally much more rank than that of Mt. Hamilton; and 
all the middle and higher slopes, even the southern and 
sunward, yield the dense thicket of brushwood usual to 
higher parts of the Coast Range proper, and also scattered 
trees, or even considerable groves, of oak and pine. Adenos- 
toma and Ceanothus cuneatus are abundant here, though 
they are absent from Mt. Hamilton and other more inland 
peaks. 
It is almost certain that no botanical collector had ascended 
Mt. Diablo before 1862, in which year Professor Brewer of 
the State Geological Survey made the ascent and brought 
from the mountain the type of several species new to science. 
From Professor Brewer’s time until now this summit has 
remained the only known locality for Streptanthus hispidus. 
Until ten years ago Phacelia Breweri, obtained as new at 
this station, by Prof. Brewer, had not been rediscovered; 
but it is now known from the hills not far back of Monterey, 
and from Mt. Hamilton. The most remarkable rediscovery 
made by the present writer while on Mt. Diablo is that of 
